Besiktas’ coach, however, has not held back in his criticism. “Karius has gone a bit stagnant, something is wrong with his electricity, motivation, enthusiasm for the game,” said Gunes. “He does not really feel a part of the team.
“It’s something we haven’t been able to work out and, of course, I am partly to blame for this.”
A FIFA spokesman confirmed they are investigating the complaint from Karius.
“We can confirm that we have received a claim from the player Loris Karius against the club Besiktas,” said a FIFA spokesman.
“The matter is currently being investigated and consequently we cannot provide any further comments.”
Telegraph Sport approached Besiktas for comment but did not reply.